X-Ray Diffraction / Reflectivity
X-Ray Diffraction and X-Ray Reflectivity
X-ray Diffraction (XRD) and X-ray reflectivity (XRR) are both X-ray analyses that can provide detailed information about crystalline materials or thin films. X-ray diffraction peaks are produced by constructive interference of monochromatic beam scattered from each set of lattice planes at specific angles. The peak intensities are determined by the atomic decoration within the lattice planes. Consequently, the X-ray diffraction pattern is the fingerprint of periodic atomic arrangements in a given material. An on-line search of a standard database for X-ray powder diffraction pattern enables quick phase identification for a large variety of crystalline samples. XRD provides information on structures, phases, preferred crystal orientations (texture) and other structural parameters such as average grain size, crystallinity, strain and crystal defects.
In XRR the X-ray beam is bounced off the film surface and the reflected beam analyzed to determine film thickness, interfacial roughness and density. The technique is useful for films ranging from 20 Å to 1 mm total thickness. Films can be single or multilayer structures, and the thickness of individual layers can be determined in minutes, with no optical constant corrections required. The films can be epitaxial, polycrystalline or amorphous.
- Bede D1 X-Ray Diffractometer